# Nuclear Chemistry Test 7

Total Questions:50 Total Time: 75 Min

Remaining:

## Questions 1 of 50

Question:The age of most ancient geological formation is estimated by

Potassium – Argon method

Carbon – 14 dating method

## Questions 2 of 50

Question:The equation $$_3L{i^6}{ + _1}{H^2} \to {2_2}H{e^4} +$$ energy represents

Synthesis of helium

Transmutation of element

Fusion reaction

Nuclear fission

## Questions 3 of 50

Question:If two light nuclei are fused together in nuclear reaction the average energy per nucleon

Increases

Cannot be determined

Remains same

Decreases

## Questions 4 of 50

Question:A wood piece is 11460 years old. What is the fraction of $$^{14}C$$ activity left in the piece? (Half-life period of $$^{14}C$$ is 5730 years)

0.12

0.25

0.5

0.75

## Questions 5 of 50

Question:A substance used as a moderator in nuclear reactors is

Uranium-235

Heavy water

## Questions 6 of 50

Question:Equation $$_{17}C{l^{37}}+{\,_1}{H^2}\to{\,_{18}}A{r^{38}}+{\,_0}{n^1}$$ is

Nuclear fission

Nuclear fusion

Transformation of chlorine

Synthesis of argon

## Questions 7 of 50

Question:$$_{13}A{l^{28}}$$ when radiated by suitable projectile gives $$_{15}{P^{31}}$$ and neutron. The projectile used is

Proton

Neutron

Alpha particle

Deuteron

## Questions 8 of 50

Question:Which of the following statements about radioactivity of an element is incorrect

It is a nuclear property

It does not involve any rearrangement of electrons

Its rate is affected by change in temperature and/or pressure

It remains unaffected by the presence of other element or elements chemically combined with it

## Questions 9 of 50

Question:Artificial radioactivity was first discovered by

Seaberg

Rutherford

Einstein

Irene Curie & Juliot

## Questions 10 of 50

Question:The half-life period of a radioactive element is 140 days. After 560 days, one gram of the element will reduce to

$$1/2\,g$$

$$1/4\,g$$

$$1/8\,g$$

$$1/16\,g$$

## Questions 11 of 50

Question:$$_{95}A{m^{241}}$$ and $$_{90}T{h^{234}}$$ belong respectively to

$$4n$$ and $$4n+1$$ radioactive disintegration series

$$4n+1$$ and $$4n+2$$ radioactive disintegration series

$$4n+1$$ and $$4n+3$$ radioactive disintegration series

$$4n+1$$ and $$4n$$ radioactive disintegration series

## Questions 12 of 50

Question:The nuclides (A nuclide is the general name for any nuclear species) $$_6{C^{12}}{,_{26}}F{e^{56}}$$ and $$_{92}{U^{238}}$$ have 12, 56 and 238 nucleons respectively in the nuclei. The total number of nucleons in a nucleus is equal to

The total number of neutrons in the nucleus

The total number of neutrons in the atom

The total number of protons in the nucleus

The total number of protons and neutrons in the nucleus

## Questions 13 of 50

Question:Number of neutrons in a parent nucleus $$X$$, which gives $$_7{N^{14}}$$ nucleus after two successive $$\beta$$ emissions would be

9

8

7

6

## Questions 14 of 50

Question:The disintegration of an isotope of sodium. $$_{11}N{a^{24}}{\to_{12}}M{g^{24}}{+_{-1}}{e^0}$$ shown is due to

The formation of a stable nuclide

The fall in the neutron : proton ratio

None of these

## Questions 15 of 50

Question:Group displacement law was given by

Becquerel

Rutherford

Soddy and Fajan

## Questions 16 of 50

Question:How many alpha particles are emitted in the nuclear transformation$$_{84}P{o^{215}}{ \to _{82}}P{b^{211}}$$

0

1

2

3

## Questions 17 of 50

Question:Starting from radium, the radioactive disintegration process terminates when the following is obtained

## Questions 18 of 50

Question:The appreciable radioactivity of uranium minerals is mainly due to

An uranium isotope of mass number 235

A thorium isotope of mass number 232

Actinium

## Questions 19 of 50

Question:The nuclear binding energy for $$Ar$$(39.962384 amu) is: (given mass of proton and neutron are 1.007825 amu and 1.008665 amu respectively)

$$343.81\;MeV$$

$$0.369096\;MeV$$

$$931\;MeV$$

None of these

## Questions 20 of 50

Question:The number $$\alpha-$$and $$\beta$$- particles emitted respectively during the transformation of $$_{90}^{232}Th\;{\rm{to}}\;_{82}^{208}Pb$$is

3, 6

6, 3

4, 6

6, 4

6, 8

## Questions 21 of 50

Question:In treatment of cancer,which of the following isotope is used

$$_{53}{I^{131}}$$

$$_{15}{P^{32}}$$

$$_{27}C{o^{60}}$$

$$_1{H^2}$$

## Questions 22 of 50

Question:Elements having different nuclear charge but the same mass number are called

Isotopes

Isobars

Isomers

Isotones

## Questions 23 of 50

Question:Which property is different for neutral atoms of the two isotopes of the same element

Number of protons

Atomic number

Number of neutrons

None of these

## Questions 24 of 50

Question:Which of the following species is isotonic with $$_{37}R{b^{86}}$$

$$_{36}K{r^{84}}$$

$$_{37}R{b^{85}}$$

$$_{38}S{r^{87}}$$

$$_{39}{Y^{89}}$$

## Questions 25 of 50

Question:$$_{18}A{r^{40}},{\,_{20}}C{a^{40}}$$ and $$_{19}{K^{40}}$$ are

Isomers

Isotopes

Isobars

Isotones

## Questions 26 of 50

Question:Atoms in hydrogen gas have preponderance of

$$_1{H^1}$$ atoms

Deuteron atoms

Tritium atoms

All the three (1), (2) and (3) are in equal proportion

## Questions 27 of 50

Question:An isotone of $$_{32}^{76}Ge$$is (one or more are correct)

$$_{32}^{77}Ge$$

$$_{33}^{77}As$$

$$_{34}^{77}Se$$

$$_{34}^{78}Se$$

## Questions 28 of 50

Question:Nucleons are

Protons and electrons

Protons and neutrons

Electrons and neutrons

Electrons, protons and neutrons

## Questions 29 of 50

Question:The reaction $$_5{B^8}{\to_4}B{e^8}{+_1}{e^0}$$ is due to

Loss of $$\alpha$$-particles

Loss of $$\beta$$-particles

Loss of positron

Electron loss

## Questions 30 of 50

Question:Positronium is the name given to an atom-like combination formed between

A positron and a proton

A positron and a neutron

A positron and $$\alpha$$-particle

A positron and an electron

## Questions 31 of 50

Question:Which one of the following statements is incorrect

Mass defect is related with binding energy

Meson’ was discovered by Yukawa

The size of the nucleus is of the order of $${10^{-12}}-{10^{-13}}cm$$

Magnetic quantum number is a measure of ‘orbital angular momentum’ of the electron

## Questions 32 of 50

Question:The introduction of a neutron into the nuclear composition of an atom would lead to a change in

The number of the electrons also

The chemical nature of the atom

Its atomic number

Its atomic weight$$_1{D^2}$$

## Questions 33 of 50

Question:How many neutrons are present in the nucleus of $$Ra$$

88

226

140

138

## Questions 34 of 50

Question:In a nuclear explosion, the energy is released in the form of

Kinetic energy

Electrical energy

Potential energy

None of these

## Questions 35 of 50

Question:An element $$_{96}{X^{227}}$$ emits $$4\alpha$$ and $$5\beta$$ particles to form new element Y. Then atomic number and mass number of Y are

93; 211

211; 93

212; 88

88; 211

## Questions 36 of 50

Question:Meson was discovered

Yukawa

Austin

Moseley

Einstein

## Questions 37 of 50

Question:Penetrating power of a-particle is

More than $$\gamma$$-rays

More than $$\beta$$-rays

Less than $$\beta$$-rays

None of these

## Questions 38 of 50

Question:$$\beta$$-particle is emitted in radioactivity by

Conversion of proton to neutron

Form outermost orbit

Conversion of neutron to proton

$$\beta$$-particle is not emitted

## Questions 39 of 50

Question:Which of the following is not deflected by magnetic field

Deuteron

Positron

Proton

Photon

## Questions 40 of 50

Question:Which of the following can be used to convert $$_7^{14}N$$ into $$_8^{17}O$$

Deuteron

Proton

$$\alpha$$-Particle

Neutron

## Questions 41 of 50

Question:The radioactive decay of $$_{35}{X^{88}}$$ by a beta emission produces an unstable nucleus which spontaneously emits a neutron. The final product is

$$_{37}{X^{88}}$$

$$_{35}{Y^{89}}$$

$$_{34}{Z^{88}}$$

$$_{36}{W^{87}}$$

## Questions 42 of 50

Question:What is the half-life of a radioactive substance if 75% of a given amount of the substance disintegrates in 30 minutes

7.5 minutes

25 minutes

20 minutes

15 minutes

## Questions 43 of 50

Question:If 2.0 g of a radioactive substance has half-life of 7 days. The half-life of 1 g sample is

7 days

14 days

28 days

35 days

## Questions 44 of 50

Question:The half-life of $$_{38}^{90}Sr$$ is 20 years. If its sample having initial activity of 8000 dis/min is taken, what would be its activity after 80 years

500 dis/min

800 dis/min

1000 dis/min

1600 dis/min

## Questions 45 of 50

Question:$$C-14$$ has a half-life of 5760 years. $$100mg$$ of a sample containing $$C-14$$ is reduced to $$25mg$$ in

11520 years

2880 years

1440 years

17280 years

## Questions 46 of 50

Question:Half-life of a radioactive element is 100 yrs. The time in which it disintegrates to 50% of its mass, will be

50 yrs

200 yrs

100 yrs

25 yrs

## Questions 47 of 50

Question:The decay of a radioactive element follows first order kinetics, as a result

Half-life period = constant $$/k$$, where $$k$$ is the decay constant

Rate of decay is independent of temperature

Rate can be changed by changing chemical conditions

The element will be completely transformed into a new element after expiry of two half-life period

## Questions 48 of 50

Question:Half-life of a radioactive substance which disintegrates by 75 % in 60 minutes, will be

120 min

30 min

45 min

20 min

## Questions 49 of 50

Question:Amount of $$_{53}{I^{128}}({t_{1/2}}=25\;\min)$$ left after 75 minutes is

$$1/6$$

$$1/4$$

$$1/8$$

$$1/9$$

## Questions 50 of 50

Question:The half-life of a radioisotope is four hours. If the initial mass of the isotope was 200 g, the mass remaining after 24 hours undecayed is